Re: Design questions?

[protek@shreve.net]

Paul,
    Here is some input.  Most people start looking at battery technology
and start thinking and pricing and come back around to lead-acid.  Many are
golf cart batteries.  When you factor cost, weight, and energy density into
the total picture it usually leads back to lead-acid.  These have certain
dangers though that you need to research such as explosion and acid.  I use
them but I have hydro-caps on each cell to recombine the hydrogen and
oxygen gas.
    My rudder system is direct hydraulics.  I have cylinders with foot
pedals connected via tubing and hoses to the cylinders that swivel the
motor.  Make the hoses and tubes large ID if possible to cut friction.  I
do not like servo actuators and this is the reason.  Most are slow and you
as the pilot will have no feedback as to where the surface is at any time.
I never thought of this cause I do not use them.  But, Harold LaTourneau
once told me that his rudder actuator system was not good without
indication of position.  You don't want to have to wait on the boat to move
to know where the control is at any given time.  I have a similar problem
with the position of my slide weight under the keel.  But I have not
created an indicator yet.  I think that the rudder and dive planes would be
a more difficult situation without feedback unlike my slide weight, because
you will have to be moving for the control surfaces to be effective.
    As far as the hatch goes, do not use a flat hatch.  You don't want to
go there.

Gary Boucher


At 05:54 PM 9/8/99 PDT, you wrote:
>Well, I'm still in the conceptual design phase of my sub. I've gotten most 
>preliminary constraints worked out with a few exceptions. Although not a 
>constraint, I'm looking for a good source of batteries. I'm looking for a 
>high power to weight ratio. Any advice or recommendations?? Also, I'm still 
>trying to design my control surface actuator. I'll probably go with a low 
>RPM motor and lead screw. Using compression cylinders includes an extra link 
>in the design that seems redundant. I don't want to design something from 
>scratch, but the actuators, solenoids, etc, that I've looked at don't seem 
>to be of optimum design for our purposes. Finally, does anyone have 
>experience with a hatch that is not semisperical?? I'm having some problems 
>with a good canopy seal that would also serve as a hatch. I tend to 
>overdesign things sometimes (especially for life and limb), and I've got 
>some designs, but they seem awkward. I'm sure if I ponder (my wife hates 
>when I do that) the problem for the next month, I'll have a good seal that 
>is quick to open and close, but it would help if there where some 
>collaboration here (credit always given where due). I'll also be making a 
>clay model of my design in the next month, then a scale model, some 
>experiments, maybe a variable pressure cavitation tunnel (anyone know what 
>that is??)or something similar for optimizing and testing the propulsion 
>system. Then come the prints (drawings). That should complete phase one. 
>Mostly gray matter type work. Well, it used to be gray, ha. Thanks for all 
>the suggestions and support so far. This has been really exciting.
>Suds
>
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